Make UI or API driven extension options navigations refocus any existing options page.

Make UI or API driven extension options navigations refocus any existing options page.

This is already the way that the options pages embedded in chrome://extensions
work. Options pages not embedded (those declared via "options_page" or with
{"open_in_tab": true} in "options_ui") currently always open in a new tab - now
it will refocus instead.

This will affect any caller of ExtensionTabUtil::OpenOptionsPage - called from
UI like the toolbar button's context menu, and from the
chrome.browser.openOptionsPage API call.

An important side-effect of all of this is that the old behavior is buggy when
a devtools window is focused (see crash report), and this fixes it. This was
impossible to trigger until we added the chrome.browser.openOptionsPage() - now
quite likely that a devtools window is focused.

BUG=430054, 463341
R=rockot@chromium.org

Committed: https://crrev.com/4427c25096a309a9aef54b563086c1dccc2ebece
Cr-Commit-Position: refs/heads/master@{#320426}

[not at google - send to devlin, 2015-03-12 21:41:33]

kalman@chromium.org changed reviewers:
+ rockot@chromium.org
- asargent@chromium.org

[Ken Rockot(use gerrit already), 2015-03-12 22:52:59]

lgtm

[not at google - send to devlin, 2015-03-12 22:55:54]

The CQ bit was checked by kalman@chromium.org

[commit-bot: I haz the power, 2015-03-12 22:56:16]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1005673002/20001

[commit-bot: I haz the power, 2015-03-13 01:56:01]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-03-13 01:57:13]

Patchset 2 (id:??) landed as
https://crrev.com/4427c25096a309a9aef54b563086c1dccc2ebece
Cr-Commit-Position: refs/heads/master@{#320426}